Coated textile machinery parts

ABSTRACT

Disclosed is a method for the coating of textile machinery parts with a composite coating bearing finely divided particles dispersed within a metallic matrix.

BACKGROUND OF THE INVENTION

[0001] The plating of articles with a composite coating bearing finely dispersed divided particulate matter is well documented. This technology has been widely practiced in the field of electroplating as well as electroless plating. The acceptance of such composite coating stems from the recognition that the inclusion of finely divided particulate matter within metallic matrices can significantly alter the properties of the coating with respect to properties such as wear resistance, lubricity, friction, thermal transfer, and appearance.

[0002] Electroless composite technology is a more recent development as compared to electrolytic composite technology. The fundamentals of composite electroless plating is documented in a text entitled “Electroless Plating Fundamentals and Applications,” edited by G. Mallory and J. B. Hajdu, Chapter 11, published by American Electroplaters and Surface Finishers Society (1990).

[0003] The evolution of composite electroless plating dates back to Oderkerken U.S. Pat. No. 3,614,183 in which a structure of composite electroless plating with finely divided aluminum oxide was interposed between electrodeposited layers to improve the corrosion resistance. Thereafter, Metzger et al, U.S. Pat. Nos. 3,617,363 and 3,753,667 extended the Oderkerken work to a great variety of particles and miscellaneous electroless plating baths. Thereafter, Christini et al in Reissue U.S. Pat. No. 33,767 further extended the composite electroless plating to the codeposition of diamond particles. In addition, Christini et al demonstrated certain advantages associated with the deposition of the barrier layer (strike) prior to the composite layer.

[0004] Feldstein in U.S. Pat. Nos. 4,358,922 and 4,358,923 demonstrated the advantages of utilizing a metallic layer above the composite layer. The overlayer is essentially free of any particulate matter. Spencer in U.S. Pat. No. 4,547,407 demonstrated the utilizing of a mixture of dual sized particles in achieving improved smoothness of coating.

[0005] Feldstein et al in U.S. Pat. Nos. 4,997,686, 5,145,517, 5,300,330, 5,863,616, and 6,306,466 B1 demonstrated utilization of particulate matter stabilizers in the deposition of uniform stable composite electroless plating. Parker in U.S. Pat. No. 3,723,078 demonstrated the codeposition of refractory metals and chromium along with composite electroless plating.

[0006] Helle et al in U.S. Pat. Nos. 4,098,654 and 4,302,374 explored special surfactant compositions in the preparation of stabilized PTFE dispersions and their subsequent utilization in electrolytic plating.

[0007] Kurosaki et al in U.S. Pat. No. 3,787,294 proposed the use of cationic stabilizers for graphite fluoride be used in electroplating with specific attention focused upon surfactants having a C—F bond in their structure.

[0008] Brown et al in U.S. Pat. No. 3,677,907, demonstrated the utilization of surfactants also having a C—F bond in their skeleton used in combination with PTFE electrolytic codeposition.

[0009] Henry et al in U.S. Pat. No. 4,830,889, demonstrated the utilization of a cationic fluorocarbon surfactant along with a non-ionic fluorocarbon surfactant for the codeposition of graphite fluoride in electroless plating baths.

[0010] Feldstein et al in U.S. Pat. No. 5,580,375 also demonstrated the use of “frozen states” to overcome the limited shelf-life associated with certain dispersions before their use in plating applications.

[0011] Kanai in U.S. Pat. No. 4,677,817 demonstrated travelers with composite carbide coatings for use in ring spinning.

[0012] Nakano et al in U.S. Pat. No. 4,698,958 demonstrated rings with a ceramic coated layer for use in ring spinning.

[0013] Feldstein in U.S. Pat. No. 5,721,055 demonstrated benefits of composite coatings with lubricating particles on spinning textile machinery parts.

[0014] Feldstein in U.S. Pat. No. 6,309,583 demonstrated the ability to enhance the thermal transfer properties of articles coated with various composite coatings.

[0015] Feldstein et al in U.S. Pat. No. 6,506,509 demonstrated the ability to and utility of producing composite layers with varying densities of codeposited particles in the plated layer along the surface of the substrate.

[0016] The above patents reflect the state of the art and they are included herein by reference.

[0017] The following patents are provided for their schematic drawings for the machinery parts of interest in this invention.

[0018] Schmid in U.S. Pat. No. 5,164,236 describes the coating of open-end rollers with a metal-carbide coating with a nickel overlay thereof. The metal-carbide is deposited by a plasma coating approach.

[0019] Herbert et al in U.S. Pat. No. 4,193,253 describes the coating of OE rotors with a silicon carbide composite coating.

[0020] In addition, Kanai in U.S. Pat. No. 4,677,817 and Nakano et al in U.S. Pat. No. 4,698,958 illustrate well certain parts useful in ring spinning.

[0021] The coating of textile machinery parts has been a commercially accepted practice, especially when applied to open-end (OE) and ring spinning operations. For example, combing rolls (beater rolls) and rotors have been coated with composite bearing wear resistance particles such as diamond and silicon carbide. Rotor shafts used for open-end spinning have been coated primarily with a composite bearing silicon carbide. Similarly, rings and travelers used in ring spinning have been used with a variety of composite and other coatings. An example of one application of the present invention is shown herein with relation to the manufacture of a textile combing roll. Referring to FIG. 1. there is shown a typical combing roll (1) having a hollow cylindrical body (2). Typically, the hollow cylindrical body is made from steel, and/or aluminum, or an aluminum alloy. Around the outer periphery of the combing roll (1) within the region between the ends is a plurality of spaced saw-toothed wires (3). The wires (3) are generally made from a ferromagnetic material e.g., steel, and may further be coated with an electroless metal composite coating or other wear-resistant coating thereon, which coating may also be present on the body (2) of the roll (1).

[0022] While it is well documented that the use of composite coatings bearing wear resistance particles extends the lifetime of machinery parts, their use creates certain potential problems as to the degradation of the physical properties of the yarn when contacted with the wear resistant coated machinery part. Accordingly, it is objective of the present invention to substitute the use of conventional materials used in and coatings used on certain textile spinning machine parts with an improved composite coating that is compatible with and provides improved results on the manufacture of certain textile materials. This criticality is becoming more pronounced as new man made fibers are developed and as the speed for the associated spinning parts is increased. The use of such particulate matter will provide a coated machinery part more friendly towards the yarn and the finish upon such yarns.

[0023] Composite electroless nickel coatings with diamond particles have been used significantly in the textile industry for roughly 20 years. One component used in this industry in the combing roll. Due to the abrasiveness of the contacting textile material, increased wear resistance is desired for these components. Combing rolls are used with many varieties of textile materials including natural and man-made fibers. The abrasiveness to the combing rolls varies depending on the variety of the fiber used and the grade of cleanliness of the fibers. One well-established measure to combat the abrasive wear of the fibers to the combing rolls is to coat some or all portions of the combing rolls (at least the teeth portion of the saw toothed wires (3) as in FIG. 1.) with a wear resistant coating. An electroless nickel composite coatings with diamond particles is the most widely used coating for this purpose. The most common specification for this coating is to apply a coating about 20-30 microns thick containing about 2040% by volume of about 2.0 micron average size diamond particles into the coating. The coating may then be overcoated with a thinner layer of electroless nickel, and is then generally heat-treated to increase the hardness and adhesion of the coating.

[0024] As is well know in the field of textile manufacturing and as can be seen on the surface of the traditional composite electroless nickel coatings used in this field, these coatings may be too rough for effective use on combing rolls processing certain types of fibers. The problem with such roughness on the surface of textile machine parts is that this roughness can destroy small fibers not fully attached to the shaft of the yarn. This creates dust in the processing of the fibers that can accumulate in the groove of a rotor cup used in rotor spinning applications. The accumulation of dust in this groove can lower yarn quality and cause yarn breaks.

[0025] These factors are especially relevant with polyester and various man-made fibers. An informative text on this matter was presented at the 44^(th) annual Technical Conference of the Society of Vacuum Coaters in April 2001 in Philadelphia, Pa. This text focuses on the processing of polyester fibers, and concurs that combing rolls used in open end spinning face substantial wear and require additional measures of wear resistant. Further, this text concurs that the traditional composite electroless nickel-diamond coating is too rough for the sensitive polyester fibers. The text, therefore, presents an alternative physical vapor deposition coating to add wear resistance without creating a part surface that is too rough for the sensitive polyester fibers. This text does not envision the possibility of replacing the large about two micron particles of the traditional composite coating with the smaller hard particles disclosed in the present invention. Similarly, suppliers of such combing rolls to the open end textile industry have developed other surface treatments designed to increase wear life of these critical parts while maintaining a surface profile compatible with various delicate textile materials. None of these methods, however, included the utility and novelty of the present invention. Moreover, these other methods suffer from various drawbacks, including high cost of manufacture and incompatibility with the substrate. Many coating or surface techniques that may be attractive in theory are not able to adhere to or replicate the complex geometry of parts that are the subject of this invention such as combing rolls, rings, travelers, rotors, and rotor shaft.

[0026] Aside from these more recent developments, users of these textile parts have used uncoated combing rolls or combing rolls coated with only a layer of conventional electroless nickel devoid of any particulate matter. The electroless nickel alone provides some added wear resistance and does not generate roughness on the surface. The added wear life provided by electroless nickel alone is less than commercially desirable for production and economic concerns. The result however is low lifetime of these critical wear parts.

[0027] More frequent replacement of worn components means additional cost for the replacement parts, and is a cost of time, labor, and lost productivity to accomplish the replacing of worn with new parts. Moreover, if the quality of the textile product produced by the spinning parts is not consistent throughout its “life”. The initial quality produced by a new spinning part is often of lower quality until the part has been used for a sufficient “break-in” period during which the part's surface achieves an equilibrium of sorts. Once the part is sufficiently worn, the quality of the product again degrades. Therefore, the longer the main lifetime of the part can be prolonged will result in an extended period of producing a product of higher and more consistent quality. The coated parts associated with the present invention provide such an extended period of consistent and quality product.

[0028] Since it is the particles in the composite coatings used to date on such textile spinning parts that cause the roughness of the coating surface, this invention relates to producing combing rolls with a composite coating incorporating particles substantially smaller than the particles used commonly in the field.

BRIEF SUMMARY OF THE INVENTION

[0029] It is an object of the present invention to improve significantly the performance of open-end and ring spinning textile machinery parts and to eliminate many of the disadvantages associated with prior art coatings.

[0030] These and other objects of the present invention together with the advantages over the existing prior art and method will become apparent from the following specification and the method described herein.

BRIEF DESCRIPTION OF THE DRAWING

[0031]FIG. 1 is an isometric view of a textile combing roll.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] According to the concept of the present invention, the composite electroless coatings bearing sub-micron particles are applied onto open-end spinning machinery parts (rotors, combing rolls, navels, spinning rings, travelers, and others). The use of such coatings by contrast to composites bearing larger particles, will result in friendlier contact between the yarn and the coated machinery parts thereby minimizing any damage(s) to the yarns and resulting in improved physical properties for the processed yarn, and economy of use in such coated machinery parts.

[0033] The use of plasma coating was found in the prior art to be of special benefit in the case of certain fibers, e.g., rayon. However, the plasma coatings are limited in lifetime due to limited wear-life and moreover it is prone to chipping which is typical of vitreous type materials. By contrast, the present composites can provide with metallic matrices having a hardness value of up to around 1100 Hv.

[0034] The following example is an illustration whereby diamond particles with a mean particle size of 250 nanometers are codeposited in a hard metallic matrix. It should be noted that the present invention is not limited to the type of bath used herein, but in general for electroless deposits of the various metals and alloys. Moreover, the invention is not limited to the specific diamond particles used. In the current example an electroless nickel plating bath, Nano-Plate 250 sold by Surface Technology, Inc., was used to provide a Ni—P type alloy. The bath was operated at a pH of 4.8 and a temperature of 188 degrees F., and a cycle time of 90 minutes. Into a plating tank of 10 liters consisting of the Nano-Plate 250 bath, a stock dispersion of Nano-Plate 250 D containing diamond particles with a mean particle size of about 150-200 nanometers was added along with DI water to produce a final volume of 11 liters. The open-end spinning machinery parts after normal cleaning and pickling were plated for 90 minutes under the above conditions. The Machinery parts were then heat treated at a temperature above 200 degrees C. A cross sectional cut revealed a significant quantity (several percent by volume) of codeposited diamond particles.

[0035] Though the present invention primarily focuses upon diamond as the particulate matter to be used in the composite coatings for the specific textile machinery parts, other particles fall within the spirit of this invention. Specifically, the use of silicon carbide, boron carbide, aluminum oxide, tungsten carbide and other hard particles fall within the spirit of this invention.

[0036] It was surprisingly found that a composite coating as produced in the above example provides a surface topography closely resembling conventional electroless nickel devoid of particles with a surface useful for these machinery parts, despite the fact that the coating under the present invention contains a significant percent of particulate matter.

[0037] Also surprising are the results of tests of the type of coating included in the present invention compared to the conventional composite coatings used on textile machinery parts. The above reference Nano-Plate 250 coating achieved a hardness of 1,161 VHN which is substantially higher than the hardness measurements of 863 VHN on a composite coating of electroless nickel with 2 micron sized diamond particles (as commonly used on such textile machinery parts). By way of reference, P2 grade tool steel has a hardness of about 400 VHN.

[0038] Further surprising results were found in the testing of the wear resistance of another version of a coating related to the present invention compared to a coating that has to date been a standard coating on textile machinery parts. A composite of diamond particles with a mean particle size of about 75 nanometers in electroless nickel matrix was prepared using an electroless nickel plating bath, Nano-Plate 150 sold by Surface Technology, Inc., to provide a Ni—P type alloy. The bath was operated at a pH of 4.8 and a temperature of 188 degrees F., and a cycle time of 90 minutes. Into a plating tank of 10 liters consisting of the Nano-Plate 150 bath, a stock dispersion of Nano-Plate 150 d containing diamond particles with a mean particle size of about 75 nanometers was added along with DI water to produce a final volume of 11 liters. Taber steel panels measuring four by four inches were plated for 90 minutes under the above conditions. The Taber panels were then heat treated above 200 degrees C. A cross sectional cut revealed a significant quantity (several percent by volume) of codeposited diamond particles.

[0039] The Taber panels prepared as disclosed above demonstrated a Taber Wear Index of 0.0013, whereas a composite coating of electroless nickel with 2 micron sized diamond particles (as commonly used on such textile machinery parts) demonstrated a Taber Wear Index of 0.0017. In the Taber test method, a coated panel turns under two rotating abrasive wheels. Wear is measured as the weight loss of the panels following a specified number of rotating cycles. The lower the wear index, the lower the wear to the coating. The results cited here are based on an extensive test of 10,000 cycles. 

What I claim is:
 1. A textile machinery part having a metallic substrate and a coating formed thereon, said coating consisting essentially of finely divided wear resistant particulate matter with an average particle size of less than one micron dispersed within a metal matrix.
 2. The machinery part according to claim 1, wherein said particulate matter is diamond.
 3. The machinery part according to claim 1, wherein said machinery part is useful in open-end spinning processing.
 4. The machinery part according to claim 1, wherein said machinery part is a combing roll useful in open-end spinning processing.
 5. The machinery part according to claim 1, wherein said machinery part is a rotor useful in open-end spinning processing.
 6. The machinery part according to claim 1, wherein said machinery part is a rotor shaft useful in open-end spinning processing.
 7. The machinery part according to claim 1, wherein said machinery part is useful in ring spinning operations.
 8. The machinery part according to claim 1, wherein said machinery part is a ring useful in ring spinning operations.
 9. The machinery part according to claim 1, wherein said machinery part is a traveler useful in ring spinning operations.
 10. The machinery part according to claim 1, wherein said metal matrix is a nickel alloy.
 11. The machinery part according to claim 1, wherein said metal matrix has a hardness value of at least 700 Hv.
 12. The machinery part according to claim 1, wherein said wear resistant particulate matter is selected from the group consisting of silicon carbide, boron carbide, aluminum oxide, tungsten carbide, and mixtures thereof.
 13. The machinery part according to claim 1, wherein said wear resistant particulate matter is selected from the group consisting of diamond, silicon carbide, boron carbide, aluminum oxide, tungsten carbide, and mixtures thereof in addition to a lubricating particulate matter.
 14. The machinery part according to claim 1, wherein said metal matrix is a nickel-phosphorous alloy.
 15. The machinery part according to claim 14, wherein said nickel-phosphorous alloy is deposited by an electroless method of deposition.
 16. The machinery part according to claim 1, wherein said coating has a portion thereof for contacting a textile yarn during use of said textile machinery part.
 17. A textile machinery part for contacting yarn during processing thereof, said machinery part having a metallic substrate and a coating formed thereon, said coating consisting essentially of finely divided wear resistant particulate matter dispersed within a metal matrix, said particulate matter having an average particle size of less than one micron.
 18. The machinery part according to claim 17, wherein said particulate matter is diamond.
 19. The machinery part according to claim 17, wherein said diamond has an average particulate size of 75 to 250 nanometers.
 20. The machinery part according to claim 18, wherein said nickel-phosphorous alloy is deposited by an electroless method of deposition.
 21. The machinery part according to claim 17, wherein said wear resistant particulate matter is selected from the group consisting of diamond, silicon carbide, boron carbide, aluminum oxide, tungsten carbide, and mixtures thereof.
 22. The machinery part according to claim 17, wherein said metal matrix is a nickel-phosphorous alloy.
 23. The machinery part according to claim 17, wherein said coating has a portion thereof for contacting a textile yarn during use of said textile machinery part.
 24. The machinery part according to claim 17, wherein said coating has been subjected to heat treatment at a temperature of at least 200.degree. C. 